Sheave and pressure rider



Aug. 10, 1943. 'J. c. PATTERSON, JR

SHEAVE AND PRESSURE RIDER Filed Aug. 21, 1941 2 Sheets-Sheet 1 Aug. 10,1943.

J. c. PATTERSON, JR 2,326,670 SHEAVEE AND PRESSURE RIDER Filed Aug. 21,1941' 2 Sheets-Sheet 2 3mm JJgwfifiallezwzgfi $2M lag/M I is carriedbetween a sheave l I and a pressure roller l2, provided with a suitablemeans for application of pressure, such as the hydraulic cylinder 2|,illustrated in Figure l. 'I'hesheave l l comprises rigid flanges l 3 anda resilient body portion M of a synthetic rubber material maintained inplace between the flanges by a plurality of clamping bolts IE. on ashaft [8 by conventional means'and the The flanges are mounted aseaevocables of different cross sectional areas. Furthermore the size of thegroove may be altered to compensate for wear by merely drawing flangesl3 together. This adjustment therefore renders installation lessdifficult and replacement less frequent.

Still greater advantages under certain drive conditions are obtained byusing asystem such as that shown in Figure 6 wherein the cable is causedto lie in the groove l8 for a large portion of the periphery of thedrive sheave I l by the use of a plurality of pressure riders I 2. Itwill be apparent that the increased contact area will prevent excessivewear of the resilient material by reducing the intensity of pressure ascontrasted with the prior art expedient of maintain- I ing positivedrive by the use of extremely high shaft 16 is provided with suitabledriving means,

not shown. In the embodiment of Figures 2, 3 and 7 the inner faces oftheflanges 13, are provided with recesses I! and the bolt l5 passes througha bore in the body Id of considerably greater diameter than the bolt.

By reference to Figure 3 it is seen also that the application ofpressure to'the cable by means of pressure roller 12 causesthe resilientbody [4 to be deformed, bulging outwardlyinto the recesses I! and alsocausin'gthe wallsof the, groove [8 to close 'in against the cable Itthus providing a much greater area of contact between thecable and thatportion of the sheave contacting therewith.

function. The importance of these recesses is their location: withrespect to the material defining groove 18 which is suchas tocause theresilient material to bend around the cable as shown in Figure 3 whenpressure is applied from the rider. Inasmuch as the ,material from whichbody portion M is composed-is deformable rather than compressible, it isevident that recesses ll' and Ila also function to-preventthe syntheticrubber material from being groundnut because of bearing against a hardsurface. g

By means of the device discussed above, it is found that wear on thecableis greatly reduced by the coaction of two factors; v Because of theadjustable gripping action of driving contact between sheave and cable,it, is possible .to use drastically reduced pressures, Furthenthe' weardue to friction between the surfaceof a metal and a resilient substanceis much less than the wear due to friction at a metal to-metal contact.Although I may use rubber or anyother resilient substance, I prefertouse the L'so-called synthetic substances because of theirgreaterresistance to deterioration in the presence of oils such as areused for lubrication and corrosion inhibition of the cable. Suchsyntheticcornpositi-ons as neoprene, Thiokof Formica and the like arefound to be eminently satisfactory. 'I have also found that the use ofthe present device results in longer life of the cable because the'tendency to squeeze out the oils used for lubrication and corrosioninhibition is greatly reduced.

In the embodiment of the inventionshown in ripheral portion of the.sheave.

pressure.

In Figure 7 there is shown a modification of the embodiment illustratedin Figure 2.. A plurality of clampinglevers J9 are provided along thevtwo edges of theresilient body in the pe- Each of the clamping levers I9is of a form similar to a bell'crank pivoted for rotation in aplaneparallel to the axis of the sheave on the inner face of flange |3. Oneleg of each lever [5 lies between; flange l3 and resilient body 14extending radially outward from the point of pivotal connection. Theother leg is embedded in r the resilient body l4 extending into "thatbody By the use .of a resilient body l4 disposed 7 between rigid flangesI3 which may be drawn together by bolts I5 it'is evident that theinitial diameter of groove I8 can be adjusted to receive and toward'theaxis of the sheave. Upon application of pressure to the cable ID thecable tends to displace a portion of the resilient body I inwardlytoward the axis of the sheave thereby acting upon the innerlegs of thelevers l9. By reason of the pivotal connection of ithe levers to theflanges IS, the outer legs of the levers are caused to exert pressureagainst the resilient body toward thecable thus accentuating theefiectillustratedinFigure 3..

I have found that efficiency of the sheave may be enhanced by providinga tread in the cable carrying groove of the resilient body M. Figure- 8illustratesa resilient body [4 having radial slots 20 extending from thesurface of the groove l8 a substantial distance into the'body 14.Preferably the depth-of the slots 20"is'si1b V stantially equal to thedepth to which the groove |8 wil1 be worn before replacement isadvisable. It will be apparent to those skilled in the art that variousmodifications and adaptations of my invention may, be made withoutdepart-.

ing from the spirit thereof. For example, it is often advisable toincorporate friction enhancingmaterials such as metal wire, fibre, hemp,

carbon, and other substances having suitable properties in the resilientbody I4. It is to be understood-that the invention is not limited to thespecific forms-illustrated and discussed, but

is limited only by --the scope of the appended claims.

What I claim is: I e

1 In the combination of asheave peripheral groove to receive a cable,rope-or belt, a rider cooperating with said groove and pressure means toapply pressure to said rider; a sheave comprising rigid circular flangesform ing sides of the sheave and each having its inner face recessedthroughouta portion'thereof intermediate the axis and the periphery ofthe sheave and a resilient body portion having a peripheral groove lyingbetween said flanges and normally ocupying the space between saidflanges having a with the exception of the space in said recessedportions. 7

2. A device as defined in claim 1 having a plurality 'of clamping leverspivotally attached to the inner faces of said flanges outwardly of saidrecessed portions, one leg of each of said levers extending radiallyoutward between said resilient body and said fiange and the other legthereof extending at an acute angle to the face of said flange into saidbody and toward the axis of the sheave.

3. In the combination of a sheave having a peripheral groove to receivea cable or the like, a rider co-operating with said groove and means toapply pressure to said rider, a sheave comprising rigid flanges formingthe sides thereof, a resilient body portion having a peripheral groove,said body portion lying between said flanges and being normally incontact therewith except in annular zones, each of which is defined,

the radial depth of the body portion being at least twice the diameterof the groove, and means passing through said Zones for drawing saidflanges toward one another to reduce the diameter or said groove,whereby to render the sheave adaptable to use with cables of differentdiameters and to allow compensation for wear of the groove. 1

' i. A device as defined in claim 1 wherein said resilient body portionisprovided with a plurality of radial slots extending inwardly from thebottom of the peripheral groove to aiiord improved cable grippingqualities.

5; A device as defined in claim 3 wherein said resilient body portion isprovided with a plurality of radial slots extending inwardly from I thebottom of the peripheral groove to afford gripping qualities.

improved cable 7 JOSEPH C. PATTERSON, JR.

at least in part, byan inner face of a flangei.

